The mid-infrared 3 to 5 μm atmospheric transmission window is important for remote sensing and spectroscopic applications because it contains many fingerprint molecular rotation-vibrational absorption lines, such as O—H stretch at 2.8 μm; N—H stretch at ˜3 μm, C—H stretch at ˜3.3 μm. Spectroscopic applications typically require a continuous wave (CW), single-longitudinal-mode (SLM) and mode-hop-free, continuously tunable, narrow spectral linewidth, high power laser source with good beam quality.
Imaging systems for identifying gas leaks are one such spectroscopic application. These systems function by emitting a laser beam through a gas and capturing an image of light with an MIR imager. The light from the laser beam is backscattered by the gas or objects positioned near the gas, or backscattered light that is absorbed by the gas. Such conventional imaging systems incorporate complex photonic integrated circuits.
There has been much interest in the design, manufacture, testing, assembly, and packaging of complex photonic integrated circuits that combine a variety of photonic and electronic components to achieve functionality. The demonstration of integrated photonic sensors that are manufacturable and scalable to reduce size, weight, power, and cost is pivotal for success in this industry. Current breadboard technologies used as integrated photonic sources contain critical alignment issues and fail to reduce size, weight, power, and cost of product.
Thus, what is needed is a more compact and tunable integrated photonic source that overcomes the limitations of current technologies.